@Micheal Mallo Thanks for posting in our Q&A.
For this issue, please check if the following reg keys are deleted:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DeviceManageabilityCSP
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\CCMSetup
If yes, please try to reboot the device and force a device sync in the target device after uninstalling the SCCM agent.
If there is anything update, feel free to let us know.
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